The present invention relates to a stator for installation in a rear section of a jet engine, the stator comprising a plurality of guide vanes which extend in the radial direction of the stator and between them define duets for leading a gas, and a first side of the stator in its axial direction defining an inlet for the gas and a second side, opposite the first side, defining an outlet for the gas. The invention further relates to a jet engine comprising the stator and an airplane comprising the jet engine.
The term jet engine is intended to include various types of engines which take in air at a relatively low velocity, heat it up through combustion and expel it at a much higher velocity. The term jet engine includes turbojet engines and turbofan engines, for example.
The jet engine conventionally comprises a compressor section for compression of the intake air, a combustion chamber for combustion of the compressed air and a turbine section arranged behind the combustion chamber, the turbine section being rotationally connected to the compressor section in order to drive this by means of the energy-rich gas from the combustion chamber. The compressor section usually comprises a low-pressure compressor and a high-pressure compressor. The turbine section usually comprises a low-pressure turbine and a high-pressure turbine. The high-pressure compressor is rotationally locked to the high-pressure turbine via a first shaft and the low-pressure compressor is rotationally locked to the low-pressure turbine via a second shaft.
The jet engine can be used for the propulsion of various types of jet-propelled craft including both land and waterborne craft, but the invention is primarily intended for applications in an aircraft, and in particular in an airplane engine.
Protecting an airplane against possible attack by giving the airplane a low so-called signature is already known. The term signature in this context refers to the contrast with the background. An airplane should have a low signature in respect of such things as infrared radiation (IR) and radar, for example. Hot structures and hot exhaust gases give rise to an IR signature. Metal surfaces of the jet engine, such as turbine parts, can give rise to an IR signature when they become hot during operation of the jet engine.
The present invention is directed towards a propulsion device for an airplane which is designed to produce a low signature.
It is desirable to provide a stator for a jet engine which will give the jet engine a reduced signature in operation. In particular it is intended to produce a reduction in the infrared radiation emitted from the jet engine. It is also desirable that the stator should afford a substantially reduced signature with minimal loss of performance in the operation of the jet engine.
According to an aspect of the present invention, a stator for installation in a rear section of a jet engine is provided, the stator comprising a plurality of guide vanes which extend in the radial direction of the stator and between them define ducts for leading a gas, and a first side of the stator in its axial direction defining an inlet for the gas and a second side, opposite the first side defining an outlet for the gas, characterized in that said guide vanes have such a shape that together they at least substantially cover said gas inlet viewed in the axial direction of the stator from the outlet side thereof.
According to an aspect of the present invention, two adjacent guide vanes overlap one another in a circumferential direction, or at least form a substantially continuous structure in a circumferential direction, viewed in the axial direction of the stator from the outlet side thereof. When the stator is installed in the jet engine, internal hot/reflective parts of the engine will be hidden from rear view.
According to a further aspect both an inlet section and an outlet section of each guide vane basically extend in an axial direction and a section between the inlet section and the outlet section extends in a direction with a component in the circumferential direction of the stator. This makes it possible to achieve an overlapping, or at least substantially continuous structure in a circumferential direction. A plurality of said guide vanes preferably have the basic cross-sectional shape of an elongated Z.
According to a further aspect at least one of said guide vanes is hollow for leading a coolant. This allows the guide vanes to be cooled in operation.
According to a further aspect the stator comprises a radially outer ring, the guide vanes being firmly connected to the outer ring and the outer ring defining an inner duct for a core flow and an outer duct for a fan flow. At least one of the guide vanes comprises a radially outer opening, which is connected to the fan air duct in order to lead a proportion of the fan air into the interior of the guide vane and to cool the guide vane. In flight it is advantageous to use the fan air flow (rather than air from the surroundings) for cooling since an advantageous pressure ratio ensues. In flight a pressure ratio of >2 relative to the ambient pressure often occurs. The fan air therefore has a relatively high pressure.